1. Field of the Invention
The present invention relates to a device for detecting net faults in tennis.
2. Prior Art
According to the playing rules of tennis, a fault is assessed when a served ball touches the net prior to impact with the opponent's court. In cases of doubt, such a fault is not always recognized because the vibrations of the net caused by the contact with the ball can no longer be detected.
DE-A-38 43 266 describes an indicator device for tennis, which consists of at least one electronic sensor installed within the top edge of the net. The sensor responds to the mechanical vibrations occurring therein due to contact of the edge with the playing ball. The sensor is arranged in an electric circuit containing an optical or audio signal emitter, and, in case of response, triggers the signal emission. A piezo glass-breaking indicator is specified as the sensor.
However, the glass-breaking indicator, is not suitable in the present case because it responds to only one frequency, that of breaking glass.